The purpose of this investigation is to obtain synchronous recordings of: 1) masticatory movements using cinefluoroscopy; 2) EMG's from the adductor, hyoid, pharyngeal and lingual musculature; and 3) strain from the body of the mandible in the crab eating macaque, Macaca fasicicularis. These results will make it possible to determine: 1) how jaw muscles control jaw movements; 2) the mechanism of food transport; and 3) the mechanism of deglutition. The relationship between the consistency of the food and the masticatory cycle, masticatory sequence and swallowing will be investigated. A pilot study on M. fascicularis has established that the methods and techniques outlined in this proposal are feasible and will yield the results we expect. Our earlier EMG and cinefluorographic studies on an insectivore (tenrec), omnivore (opossum), herbivore (hydrax), and carnivore (cat) have shown that in all these mammals there is a consistent relationship between jaw, hyoid and intratongue movements throughout the masticatory sequence, including swallowing. As a result, it is always possible to divide the masticatory cycle up into four clear divisions. These reflect the interrelationships between the breaking down of food by the jaws and the transport of food by the tongue. It was shown that swallowing always occurs in the middle of the slow opening phase. This investigation will help to establish whether mastication, transport and swallowing in primates conforms to a general mammalian pattern. Only isolated parts of these phenomena have been studied in primates, including man. A study that integrates the movements and muscle activity involved in the processing and transport of food in the oral cavity and pharnyx in a primate will provide essential baseline information. This is fundamental to the diagnosis of oral malfunction and the design of both operative and rehabilitation techniques.